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elf.c @ 205

Last change on this file since 205 was 204, checked in by alain, 7 years ago

Bug fix in kernel_init
-This line, and those below, will be ignored--

M params.mk
M kernel_config.h
M Makefile
M hdd/virt_hdd.dmg
M tools/bootloader_tsar/boot.c
M kernel/libk/bits.h
M kernel/libk/elf.c
M kernel/libk/xhtab.c
M kernel/libk/elf.h
M kernel/libk/xhtab.h
M kernel/devices/dev_pic.c
M kernel/mm/vmm.c
M kernel/mm/mapper.c
M kernel/mm/mapper.h
M kernel/vfs/devfs.h
M kernel/vfs/vfs.c
M kernel/vfs/vfs.h
M kernel/vfs/devfs.c
M kernel/kern/chdev.h
M kernel/kern/kernel_init.c
M kernel/kern/process.c
M kernel/kern/process.h
M hal/tsar_mips32/core/hal_remote.c
M hal/tsar_mips32/drivers/soclib_pic.c

File size: 10.5 KB

Line
1	/*
2	* elf.c - elf parser: find and map process CODE and DATA segments
3	*
4	* Authors Alain Greiner (2016)
5	*
6	* Copyright (c) UPMC Sorbonne Universites
7	*
8	* This file is part of ALMOS-MKH.
9	*
10	* ALMOS-MKH is free software; you can redistribute it and/or modify it
11	* under the terms of the GNU General Public License as published by
12	* the Free Software Foundation; version 2.0 of the License.
13	*
14	* ALMOS-MKH is distributed in the hope that it will be useful, but
15	* WITHOUT ANY WARRANTY; without even the implied warranty of
16	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17	* General Public License for more details.
18	*
19	* You should have received a copy of the GNU General Public License
20	* along with ALMOS-MKH; if not, write to the Free Software Foundation,
21	* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22	*/
23
24	#include <kernel_config.h>
25	#include <hal_types.h>
26	#include <hal_uspace.h>
27	#include <printk.h>
28	#include <process.h>
29	#include <vseg.h>
30	#include <kmem.h>
31	#include <vfs.h>
32	#include <elf.h>
33	#include <syscalls.h>
34
35	///////////////////////////////////////////////////////////////////
36	// This static function checks the .elf header.
37	// - return true if legal header.
38	// - return false with an error message if illegal header.
39	///////////////////////////////////////////////////////////////////
40	static bool_t elf_isValidHeader(Elf32_Ehdr *header)
41	{
42	if((header->e_ident[EI_CLASS] == ELFCLASS32)
43	&& (header->e_ident[EI_DATA] == ELFDATA2LSB)
44	&& (header->e_ident[EI_VERSION] == EV_CURRENT)
45	&& (header->e_ident[EI_OSABI] == ELFOSABI_NONE)
46	&& ((header->e_machine == EM_MIPS) \|\|
47	(header->e_machine == EM_MIPS_RS3_LE) \|\|
48	(header->e_machine == EM_X86_64))
49	&& (header->e_type == ET_EXEC))
50	return true;
51
52	if( header->e_ident[EI_CLASS] != ELFCLASS32 )
53	printk("\n[ERROR] in %s : Elf is not 32-Binary\n", __FUNCTION__ );
54
55	if( header->e_ident[EI_DATA] != ELFDATA2LSB )
56	printk("\n[ERROR] in %s : Elf is not 2's complement, little endian\n", __FUNCTION__ );
57
58	if( header->e_ident[EI_VERSION] != EV_CURRENT )
59	printk("\n[ERROR] in %s : Elf is not in Current Version\n", __FUNCTION__);
60
61	if( header->e_ident[EI_OSABI] != ELFOSABI_NONE )
62	printk("\n[ERROR] in %s : Unexpected Elf ABI, need UNIX System V ABI\n", __FUNCTION__ );
63
64	if( (header->e_machine == EM_MIPS) \|\|
65	(header->e_machine == EM_MIPS_RS3_LE) \|\|
66	(header->e_machine == EM_X86_64) )
67	printk("\n[ERROR] in %s : unexpected core / accept only MIPS or x86_64\n", __FUNCTION__ );
68
69	if( header->e_type == ET_EXEC )
70	printk("\n[ERROR] in %s : Elf is not executable binary\n", __FUNCTION__ );
71
72	return false;
73	}
74
75	///////////////////////////////////////////////////////////////////////////////////////
76	// This function loads the .elf header in the buffer allocated by the caller.
77	///////////////////////////////////////////////////////////////////////////////////////
78	// @ file : extended pointer on the remote file descriptor.
79	// @ buffer : pointer on buffer allocated by the caller.
80	// @ size : number of bytes to read.
81	///////////////////////////////////////////////////////////////////////////////////////
82	static error_t elf_header_load( xptr_t file_xp,
83	void * buffer,
84	uint32_t size )
85	{
86	uint32_t count;
87
88	// load .elf header
89	count = vfs_move( true ,
90	file_xp,
91	buffer,
92	size );
93
94	if( count != size )
95	{
96	printk("\n[ERROR] in %s : failed to read ELF header\n", __FUNCTION__ );
97	return -1;
98	}
99
100	Elf32_Ehdr * header = (Elf32_Ehdr *)buffer;
101
102	if( (header->e_ident[EI_MAG0] != ELFMAG0) \|\|
103	(header->e_ident[EI_MAG1] != ELFMAG1) \|\|
104	(header->e_ident[EI_MAG2] != ELFMAG2) \|\|
105	(header->e_ident[EI_MAG3] != ELFMAG3) )
106	{
107	printk("\n[ERROR] in %s : file %s not in ELF format\n", __FUNCTION__ );
108	return -1;
109	}
110
111	if( !(elf_isValidHeader( header ) ) )
112	{
113	printk("\n[ERROR] in %s : not supported Elf\n", __FUNCTION__ );
114	return -1;
115	}
116	return 0;
117
118	} // end elf_header_load()
119
120	///////////////////////////////////////////////////////////////////////////////////////
121	// This function registers in the process VMM the CODE and DATA segments.
122	///////////////////////////////////////////////////////////////////////////////////////
123	// @ file : extended pointer on the remote file descriptor.
124	// @ segs_base : local pointer on buffer containing the segments descriptors array
125	// @ segs_nr : number of segments in segment descriptors array.
126	// @ process : local pointer on process descriptor.
127	///////////////////////////////////////////////////////////////////////////////////////
128	static error_t elf_segments_load( xptr_t file_xp,
129	void * segs_base,
130	uint32_t nb_segs,
131	process_t * process )
132	{
133	error_t error;
134	uint32_t index;
135	uint32_t file_size;
136	uint32_t mem_size;
137	intptr_t start;
138	uint32_t type;
139	uint32_t flags;
140	uint32_t offset;
141	vseg_t * vseg;
142
143	Elf32_Phdr * seg_ptr = (Elf32_Phdr *)segs_base;
144
145	// loop on segments
146	for( index = 0 ; index < nb_segs ; index++ , seg_ptr++ )
147	{
148	if( seg_ptr->p_type != PT_LOAD)
149	continue;
150
151	// get segment attributes
152	start = seg_ptr->p_vaddr;
153	offset = seg_ptr->p_offset;
154	file_size = seg_ptr->p_filesz;
155	mem_size = seg_ptr->p_memsz;
156	flags = seg_ptr->p_flags;
157
158	// check alignment
159	if( start & CONFIG_PPM_PAGE_MASK )
160	{
161	printk("\n[WARNING] in %s : segment base not aligned = %x\n",
162	__FUNCTION__, start );
163	}
164
165	// check size
166	if( file_size != mem_size )
167	{
168	printk("\n[WARNING] in %s : base = %x / mem_size = %x / file_size = %x\n",
169	__FUNCTION__, start , mem_size , file_size);
170	}
171
172	// set seek on segment base in file
173	error = vfs_lseek( file_xp,
174	offset,
175	SEEK_SET,
176	NULL );
177
178	if( error )
179	{
180	printk("\n[ERROR] in %s : failed to seek\n", __FUNCTION__ );
181	return -1;
182	}
183
184	if( flags & PF_X ) // found CODE segment
185	{
186	type = VSEG_TYPE_CODE;
187	process->vmm.code_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
188
189	elf_dmsg("\n[INFO] %s found CODE vseg / base = %x / size = %x\n",
190	__FUNCTION__ , start , mem_size );
191	}
192	else // found DATA segment
193	{
194	type = VSEG_TYPE_DATA;
195	process->vmm.data_vpn_base = start >> CONFIG_PPM_PAGE_SHIFT;
196
197	elf_dmsg("\n[INFO] %s found DATA vseg / base = %x / size = %x\n",
198	__FUNCTION__, start , mem_size );
199	}
200
201	// register vseg in VMM
202	vseg = (vseg_t *)vmm_create_vseg( process,
203	start,
204	mem_size,
205	type );
206	if( vseg == NULL )
207	{
208	printk("\n[ERROR] in %s : cannot map segment / base = %x / size = %x\n",
209	__FUNCTION__ , start , mem_size );
210	return -1;
211	}
212
213	vfs_file_count_up( file_xp );
214	}
215
216	return 0;
217
218	} // end elf_segments_load()
219
220	///////////////////////////////////////////////
221	error_t elf_load_process( char * pathname,
222	process_t * process)
223	{
224	kmem_req_t req; // kmem request for program header
225	Elf32_Ehdr header; // local buffer for .elf header
226	void * segs_base; // pointer on buffer for segment descriptors array
227	uint32_t segs_size; // size of buffer for segment descriptors array
228	xptr_t file_xp; // extended pointer on created file descriptor
229	uint32_t file_id; // file descriptor index (unused)
230	uint32_t count; // bytes counter
231	error_t error;
232
233	elf_dmsg("\n[INFO] %s : enter for %s\n", __FUNCTION__ , pathname );
234
235	// avoid GCC warning
236	file_xp = XPTR_NULL;
237	file_id = -1;
238
239	// open file
240	error = vfs_open( process->vfs_cwd_xp,
241	pathname,
242	O_RDONLY,
243	0,
244	&file_xp,
245	&file_id );
246	if( error )
247	{
248	printk("\n[ERROR] in %s : failed to open file %s\n", __FUNCTION__ , pathname );
249	return -1;
250	}
251
252	elf_dmsg("\n[INFO] %s : file %s open\n", __FUNCTION__ , pathname );
253
254	// load header in local buffer
255	error = elf_header_load( file_xp ,
256	&header,
257	sizeof(Elf32_Ehdr) );
258	if( error )
259	{
260	printk("\n[ERROR] in %s : cannot get header file %s\n", __FUNCTION__ , pathname );
261	vfs_close( file_xp , file_id );
262	return -1;
263	}
264
265	elf_dmsg("\n[INFO] %s : loaded elf header for %s\n", __FUNCTION__ , pathname );
266
267	if( header.e_phnum == 0 )
268	{
269	printk("\n[ERROR] in %s : no segments found\n", __FUNCTION__ );
270	vfs_close( file_xp , file_id );
271	return -1;
272	}
273
274	// compute buffer size for segment descriptors array
275	segs_size = sizeof(Elf32_Phdr) * header.e_phnum;
276
277	// allocate memory for segment descriptors array
278	req.type = KMEM_GENERIC;
279	req.size = segs_size;
280	req.flags = AF_KERNEL;
281	segs_base = kmem_alloc( &req );
282
283	if( segs_base == NULL )
284	{
285	printk("\n[ERROR] in %s : no memory for segment descriptors\n", __FUNCTION__ );
286	vfs_close( file_xp , file_id );
287	return -1;
288	}
289
290	// set seek pointer in file descriptor to access segment descriptors array
291	error = vfs_lseek( file_xp , header.e_phoff, SEEK_SET , NULL );
292
293	if( error )
294	{
295	printk("\n[ERROR] in %s : cannot seek for descriptors array\n", __FUNCTION__ );
296	vfs_close( file_xp , file_id );
297	req.ptr = segs_base;
298	kmem_free( &req );
299	return -1;
300	}
301
302	// load seg descriptors array to local buffer
303	count = vfs_move( true,
304	file_xp,
305	segs_base,
306	segs_size );
307
308	if( count != segs_size )
309	{
310	printk("\n[ERROR] in %s : cannot read segments descriptors\n", __FUNCTION__ );
311	vfs_close( file_xp , file_id );
312	req.ptr = segs_base;
313	kmem_free( &req );
314	return -1;
315	}
316
317	elf_dmsg("\n[INFO] %s loaded segments descriptors for %s \n", __FUNCTION__ , pathname );
318
319	// register loadable segments in process VMM
320	error = elf_segments_load( file_xp,
321	segs_base,
322	header.e_phnum,
323	process );
324	if( error )
325	{
326	vfs_close( file_xp , file_id );
327	req.ptr = segs_base;
328	kmem_free( &req );
329	return -1;
330	}
331
332	// register process entry point in VMM
333	process->vmm.entry_point = (intptr_t)header.e_entry;
334
335	// register extended pointer on .elf file descriptor
336	process->vfs_bin_xp = file_xp;
337
338	// release allocated memory for program header
339	req.ptr = segs_base;
340	kmem_free(&req);
341
342	elf_dmsg("\n[INFO] %s successfully completed / entry point = %x for %s]\n",
343	__FUNCTION__, (uint32_t) header.e_entry , pathname );
344
345	return 0;
346
347	} // end elf_load_process()
348

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